SparkFun Forums

[vicviper789]

I am new to programing and just got my max7456 on a break out board from spark fun. I want to eventually make a simple OSD for an FPV airplane but mostly learn how to program better. I am using a Duemilnove to control it.

I have read this entire thread:

http://www.arduino.cc/cgi-bin/yabb2/YaB ... 20054359/0


http://www.arduino.cc/cgi-bin/yabb2/YaB ... 1254778402

It gives me code and I make an attempt to hook it up. My screen just stays black like there is no signal. I assumed this part of the code tells me what to plugs to use.

DATAOUT 11//MOSI
DATAIN 12//MISO
SPICLOCK 13//sck
MAX7456SELECT 10//ss
VSYNC 2// INT0

I had Dout on 11, Din on 12, sck on 13, wasnt sure what ss was so I assumed CS on 10 and vsync on 2 (all digital side) Thats exactly how I had it. From reading further into the thread, I have to put a resistor on the RST pin and put 5v into it. Not sure if there are other things to do or not but I am pretty confused on how to hook it up. Any help would be appreciated

[vicviper789]

I looked further into it and it looks like i need Hyper terminal to burn the data to the board. Where can I get hyper terminal? it looks like it cost $60

[SFE-Robert]

Hyperterminal comes with Windows!

Start > Programs > Accessories > Communications

[vicviper789]

Not in windows 7, I was unable to find it if it was there. I did find it in my XP partition though

http://www.windowsreference.com/windows ... -in-vista/


I made some progress. I connected RST to 5+ and now the video is on the screen but I can not see any OSD functions.

I got the maxim eval software and when I have the arduino hooked up and serial monitor closed, it says:

Make certain:
1. The EVKit is connected to serial port
2. Make sure EVkit is powered (LED ON)
3. Another application is not using the com port
4. EVkit is not in demo mode


When I run the serial print from arduino software, the maxim software says:

Make certain:
1. Another application is not using the com port

If I close the serial port it takes me back to the first error screen. It seems the arduino isnt sharing the com port like it should (if i should?)

[SFE-Robert]

Yeah, it sounds like you are trying to use the serial port in the maxim software and the serial monitor. only one program can see the serial port at a time.

and for everyone's knowledge, TeraTerm is free and a good substitute for hypeterminal. I forgot that Windows 7 and Vista don't have hyperterminal.

[vicviper789]

Its alright, how could I use the maxim software to program the 7456? I think the real problem is the arduino not sharing the port because when I use hyper terminal, the RX light blinks on the board, not the max7456. Is there a way to hook the max7456 straight up to the computer or am I just missing something?

[SFE-Robert]

There is no 'sharing' with ports. One device connects to the serial port, that's it. You can't share.

Have you modified the code at all? You need to upload the code to the Arduino, connect everything together, and that's that.

What are you trying to use a terminal program for?

[vicviper789]

I read this thread,
http://www.arduino.cc/cgi-bin/yabb2/YaB ... 20054359/0

I started off unable to see any video at all. I shortened the wires to about 1" and now I get the MAX7456 to pass video but no OSD.

I quote post #30 of the thread (page 3)

Quote:
1. I have to get an arduino board and connect it to my MAX7456 board via the SPI interface
2. I then upload the sketch to the arduino board using the Arduino UI and run it
3. After that I use hyper terminal to send the MCM code to the arduino which in turn decodes it and sends it to the MAX7456 for burning
4. What protocol do you use to send the file from hyper terminal ?
5. Will any arduino board do, or do I have to get a certain model?


This is exactly correct. I know this seems like a rather lot of work to go through but you only have to do once per MAX7456.

While you don't have to do this with an Arduino it is the easiest way. Down load the Maxim evaluation kit software, this will allow you to modify your MCM file (really just a big text file) and add any custom characters you want. You could start with the MCM file I made (see Reply #8), it has the proper ascii order and a lot of blank space.

With HyperTerminal you use the option 'Send Text File' in uploading.

Yes any arduino type board should be fine, I've use both an Arduino Diecimila and a NKC Freeduino. I suppose I would recommend buying a 'real' Arduino for the few dollars more. It helps support the cause.

Good luck
dfraser

I downloaded the files on this website which is what he used (Post 57, page 4)
http://mysite.ncnetwork.net/res12f4fa/index.html

The arduino is connected just as he has it in the "max7456_shield_schematic" file in the folder named "Max7456+arduino files from forum" > "1-max7456_shield"

The 3 sketches compile and load but I am not sure where to go. He says use hyper terminal to send the MCM files and the MDM file to the max7456 , I am not sure if it is working because nothing happens or it says "cannot communicate" or something similar.

When I run the maxim software, it just says the com port is in use or there is nothing at all being detected.

[SFE-Robert]

Once again, you cannot have two devices connected to the serial port at the same time. If you have a terminal program open, you cannot use the software as well.

I re-read through the forum posts and all the information is there. I think you just need a better basic understanding of how these things all function. You should not need additional software. An Arduino sketch (like the many posted) loaded onto the Arduino board and properly connected to the breakout board is all you need. Pass video through it, and then modify the code so that it displays something over the video. You are getting very complicated in needing to use hyperterminal, other software, etc. Stick to the basics.

[vicviper789]

I am still new, if you could guide me, that would be a lot of help. I was only trying to use one program at a time, but I thought they said to use hyperterminal to send the file to the max7456.

[vicviper789]

I changed .mcm to .txt, didnt work, so I changed it back and hit enter a few times in the rename area. Unplugged video in, and the sketch uploaded just fine.
Did the same for the mdm file. There is a 2nd mcm file in the mdm utility folder, what is that one used for? anyone know?

Now I just need to figure out how to actually program the thing..

[SFE-Robert]

There is nothing to really program. The Arduino you have connected will control it and send it commands.

If you are using the software from MAX, I am not really sure how to do that. Following the thread closely should get everything to work. You are at step 30 trying to get everything to work. You need to start at step 1, and go slowly and make sure everything works step by step.

[vicviper789]

I think I am rushing it too much. Im sure its not difficult but it is when you dont know where to start. Im not sure how to program the max. I think it works by sending a command with SPI to turn on a character at a redetermined location in the MDM file. I need a little boost to get me spun up on how the max7456 works though, or just an awesome tutorial.

[SFE-Robert]

the resources in that thread should be a good guide for you.

you are not programming the chip, you are sending it the necessary commands via SPI from the Arduino.

[variador]

This is almost where I am at with the breakout board. It works without changing the character set. The only sketch I have found overlays SAMPL E in white blinking letters in the middle of the screen. There are a few things to get from this sketch but it would help to have other sketches to work with. Can anyone point me at other sketches that don't require changing the character set?
Thanks